water spray cooling

[Lc_shi]

I've heard that there're water spray cooling applying to air cooled condenser to lower the condensing temp. How about this tech? Is there any other concerns except scaling\corrosion etc? thx!

[chemi-cool]

you only get a blocked condenser with scale, hopeless adventure.

[BigJon3475]

Yes they are claiming massive effciency gain....They have a unique filter to stop corrosion/scaling.....They come with DIY install instructions....


With that they have no temp sensor so they will run like that in the winter or 120* weather. You can imagine what problems this could lead to. In general I will say they help when the capacity is maxed out and the temps start rising in the home above desired set point. It turns the system that was not designed to be an evaporitve cooler into an evaporative cooler....I'm sure you can see problems with this also....I wouldn't recommend it to any unless they don't like their system or they are an HVAC tech and can set the system up to operate as close as you can get.


read their site:http://www.coolnsave.com/

P.S. we went round for round with their engineer on another site.

[keepitcool]

Is the question regarding industrial, commercial or residential? I have seen it done in medium to large size applications with some success.

[ptsac]

I've heard that there're water spray cooling applying to air cooled condenser to lower the condensing temp. How about this tech? Is there any other concerns except scaling\corrosion etc? thx!

Google ecomesh adiabatic. I know of three installations in the UK and one in Netherlands. If set up correctly the coils should not get wet.

[BigJon3475]

And then you'll need to start adding all kinds of devices to control the system when in low load situations....wither it be cut the water on those conditions or cycling the cond. motor..

By the way is water cheap?....if not it won't be worth it.


By the way I have tested my tap water and it's considered acidic in the winter time so I never could figure out how a filter is going to balance the water so it doesn't form scale or become acidic....I have to add chemicals to the pool to get it "balanced".

[GXMPLX]

By the way I have tested my tap water and it's considered acidic in the winter time so I never could figure out how a filter is going to balance the water so it doesn't form scale or become acidic....I have to add chemicals to the pool to get it "balanced".

You won't get scale nor corrosion because the water is evaporated before it reaches the coils... if it is correctly installed of course or else you will see scale et all.

The only thing this does is lower the inlet air temperature lowering it near wet bulb temperautre and not dry bulb which is higher.

Two problems remain: chemi-cool has hard water and unless treated with expensive filter or cristals (like the ones used in dish washers=expensive) will form scale in the water injectors.

The second prblem is that the discharge air is oversaturated with water and will condense in the nearest cool surface or anywhere if the air cools again causing mold and mildew problems. Whether this happens within the air contidioner area is installation dependant.

And another problem, in some areas where this could be efficient because of low ambient relative humidity (you get a better temperature difference DB-WB) the water is usually expensive.

[BigJon3475]

You won't get scale nor corrosion because the water is evaporated before it reaches the coils... if it is correctly installed of course or else you will see scale et all.

The only thing this does is lower the inlet air temperature lowering it near wet bulb temperautre and not dry bulb which is higher.

Two problems remain: chemi-cool has hard water and unless treated with expensive filter or cristals (like the ones used in dish washers=expensive) will form scale in the water injectors.

The second prblem is that the discharge air is oversaturated with water and will condense in the nearest cool surface or anywhere if the air cools again causing mold and mildew problems. Whether this happens within the air contidioner area is installation dependant.

And another problem, in some areas where this could be efficient because of low ambient relative humidity (you get a better temperature difference DB-WB) the water is usually expensive.

I respectfully disagree.

Without actual water chemistry measurements however it would be hard for me to explain. Also the basic understanding of water and it's balance is also needed.

If the PE and Chemical Engineer couldn't satisfy my questions with an answer other than *industry secret* I don't see anyone else being able to.

But all the discussion would be worthless without water samples from the OP.

pH, alkalinity, water temp, total dissolved solids, calcium level.

[Lc_shi]

if water is treated and soften,there're should be low possibility to scale. Am I correct?

[GXMPLX]

I respectfully disagree.

As my wife says, I reached an age I repeat myself, but quoting myself in other posts “I don’t hold the flame of truth”… necessarily

Without actual water chemistry measurements however it would be hard for me to explain. Also the basic understanding of water and it's balance is also needed.

Good. You are not a chemist, neither am I.

If the PE and Chemical Engineer couldn't satisfy my questions with an answer other than *industry secret* I don't see anyone else being able to.
But all the discussion would be worthless without water samples from the OP.

pH, alkalinity, water temp, total dissolved solids, calcium level.

If your water is not good to be used in an evaporative cooler then don’t use it or treat and or filter it until it becomes usable.

There are acids in all water indeed carbonic acid is in the air and is dissolved in water but corrosion is limited in evaporative condensers.

In this case you will get much less corrosion than in an evaporative cooler because the water is evaporated before it touches the coil.

Some things you cannot evaporate from water and that is calcium carbonates that will plug your spray, because much evaporation takes place in the spray itself, but if you formed a droplet and it gets carried away in an air stream it will evaporate.

Dissolved matter will either evaporate with it (like carbonic acid) or crystallize or concentrate in the water left. If it does not anyway you would get it in a tiny droplet that most probably will be carried away.

If it does not and reaches the fins, there is no water in the fins to ionize it and accelerate any chemical reaction. It could cause corrosion, yes. This would render the spray useless probably not.

This is my honest opinion, that as yours needs proof! I am surely not going to set up experiments to try to prove it, I’ll let the manufacturer of this stuff do it!

Feel free to buy it and try it ... or not.

[BigJon3475]

As my wife says, I reached an age I repeat myself, but quoting myself in other posts “I don’t hold the flame of truth”… necessarily



Good. You are not a chemist, neither am I.



If your water is not good to be used in an evaporative cooler then don’t use it or treat and or filter it until it becomes usable.

There are acids in all water indeed carbonic acid is in the air and is dissolved in water but corrosion is limited in evaporative condensers.

In this case you will get much less corrosion than in an evaporative cooler because the water is evaporated before it touches the coil.

Some things you cannot evaporate from water and that is calcium carbonates that will plug your spray, because much evaporation takes place in the spray itself, but if you formed a droplet and it gets carried away in an air stream it will evaporate.

Dissolved matter will either evaporate with it (like carbonic acid) or crystallize or concentrate in the water left. If it does not anyway you would get it in a tiny droplet that most probably will be carried away.

If it does not and reaches the fins, there is no water in the fins to ionize it and accelerate any chemical reaction. It could cause corrosion, yes. This would render the spray useless probably not.

This is my honest opinion, that as yours needs proof! I am surely not going to set up experiments to try to prove it, I’ll let the manufacturer of this stuff do it!

Feel free to buy it and try it ... or not.

With low relative humidity....What happens when relative humidity increase past a certain point....is it still freely evaporating completely?

I'm not a chemist but I do follow regulations and do understand water chemistry....I have to by law.

Question.....Why wouldn't mfg's make this is an add on if it was a wonderful idea?


Why wouldn't they just make water cooled condenser instead of air cooled.....

I can promise you even when water is well above 7.0 it can still be very acidic. It needs chemicals like sodium bi carbonate and calcium chloride to not be corrosive.....If evaporating the moisture as you say leaves none of those behind It would only be a matter of time before it destroyed the coil.....of an air cooled cond.


Again he didn't ask about evaporative cooling condensers.....he asked about converting air cooled cond. into evaporative cooling condensers.


My main concern isn't the corrosion though as I stated earlier.....My main concern is low indoor loads....high relative humidity outside....and conditions where outdoor temps drop.

Have you soaked a cond. coil and watched the pressures?


If it only came on when the capacity of the air cooled cond. was maxed out then it might be a viable option.....how many protective devices must one put on to make sure they aren't called out every 70*F day for a frozen evaporator.

[BigJon3475]

if water is treated and soften,there're should be low possibility to scale. Am I correct?

Scale would be reduced with a filter. However without the water being balanced and being known it would be balanced it would most likely be very acidic.

I don't have the mister so I can spray the mist into a container and test it.

I would not normally quote another forum however it seems prudent in this case:

http://hvac-talk.com/vbb/showthread....ghlight=mister

Some of the post can be ignored as they were just trolling...However you will see the educated responses especially from the guy called Shophound.

The PE had every single chance to accurately debate the subject and provide accurate information. You can make a decision for yourself if you want to test it out or not....I see no reason to re engineer something that works fine.

[GXMPLX]

With low relative humidity....What happens when relative humidity increase past a certain point....is it still freely evaporating completely? .

Past saturation point you get fog it should not work in this conditions I agree. In the place I work this is hardly possible because of low relative humidity. But here water is hard and expensive so these devices don’t work well for other reasons.

Question.....Why wouldn't mfg's make this is an add on if it was a wonderful idea?

This is not an add but an open discussion.

I think it IS a wonderful idea, but is not new it’s like a century old and it has several drawbacks like the cost of treating water and the point you made that it is not necessary under all working conditions of the system. So like any wonderful idea it has its pros and cons.

I’ve seen this implemented in several different ways all have problems but they do save energy. But corrosion is not one of those problems (not that it will never be in all systems and all working conditions!)

Why wouldn't they just make water cooled condenser instead of air cooled.....

Because they need an expert in water treatment like yourself and you very well know this is expensive and a never ending process.

People who don’t may get into real trouble like legionella causes.

Air cool has lower maintenance costs. But somebody already made this decision, the point is do you want to save energy given you have an air cooled condenser. What I’m saying is you do, but it is not free you do have problems though we do not agree on what the main problems are.

You surely live in a high humidity zone. I don’t see the point of using them there. WB-DB is too low for it to do any good and mold and mildew are a MAJOR problem.

I can promise you even when water is well above 7.0 it can still be very acidic. It needs chemicals like sodium bi carbonate and calcium chloride to not be corrosive.....If evaporating the moisture as you say leaves none of those behind It would only be a matter of time before it destroyed the coil.....of an air cooled cond.

Corrosion cannot be explained by PH only, low PH can be corrosive high PH also, PH 7 also may be corrosive because PH measures ion concentrations but if you have an electric current you get lots of corrosion in PH 7 solutions too.

What I said is that if this device is installed correctly it should not have the coil wet.

I’m not a chemist but having acidic solutions with PH above 7 beats me! Shouldn’t they be corrosive basic solutions????

Again he didn't ask about evaporative cooling condensers.....he asked about converting air cooled cond. into evaporative cooling condensers.

Yes but there you do have corrosion. I said it as an example.

My main concern isn't the corrosion though as I stated earlier.....My main concern is low indoor loads....high relative humidity outside....and conditions where outdoor temps drop.

Have you soaked a cond. coil and watched the pressures?

As I said high relative humidity outside takes almost all the benefits away.

No, I don’t solve condensing pressure problems soaking the cond, and this is also not what the device should do.

If it only came on when the capacity of the air cooled cond. was maxed out then it might be a viable option.....how many protective devices must one put on to make sure they aren't called out every 70*F day for a frozen evaporator.

I agree it should have a thermostat/higrostat to turn it on and is another device that could fail.

The temperature difference between Dry bulb and Web bulb (maximum potential improvement of this device) of the air entering the condenser will hardly produce frozen evaporators unless it has another problem simultaneously.

In my opinion.

[BigJon3475]

Water tries it's best to be balanced.....that means if it's scaly it will try and leave that scale behind......If it's acidic it's going to try and take the chemicals it needs to try and be more balanced....It doesn't matter what material it is if it's metal, concrete, skin, hair....ect. Anywhere the chemicals are...

Sorry I'm not very diplomatic with my responses sometimes they sound negative when I just don't know how to properly type


I agree it can be used and it's no where near a new idea.

[GXMPLX]

OK let's see if we agree now, (if not help me with this list):

The main function of devices spraying water in the air current is to lower the temperature of the air from dry bulb temperature to wet bulb temperature which is lower.

This makes the system work at a slightly lower condensing temperature and therefore save energy.

The problems are (not necessarily in order of importance):
- Cost of water.
- Water treatment.
- Condenser corrosion.
- Device control (in general it is not beneficial under all working conditions of the system).

It should not be used if any of the following are present
- High ambient relative humidity
- Mold and mildew are of concern
- Nearby surfaces with an external temperature lower than the discharged air dew point
- If fog is seen in the condenser air discharge under any working condition

[BigJon3475]

OK let's see if we agree now, (if not help me with this list):

The main function of devices spraying water in the air current is to lower the temperature of the air from dry bulb temperature to wet bulb temperature which is lower.

This makes the system work at a slightly lower condensing temperature and therefore save energy.

The problems are (not necessarily in order of importance):
- Cost of water.
- Water treatment.
- Condenser corrosion.
- Device control (in general it is not beneficial under all working conditions of the system).

It should not be used if any of the following are present
- High ambient relative humidity
- Mold and mildew are of concern
- Nearby surfaces with an external temperature lower than the discharged air dew point
- If fog is seen in the condenser air discharge under any working condition

pretty much....

How much is the slight energy savings worth. The company I refer to claims 30% savings but was not doing accurate testing. I'm all for saving money but their engineers only reply was it lowers compression ratio and that's it that's how you save 30%.

I would have expected a long drawn out answer from an engineer. However he was only repeating himself constantly and refering back to his almost minimal testing.

I will admit they went full out engineering on explain how the mister "mists" Why not do the same with the energy savings after all that's why people would be buying it for.

I can't see it being worth it...but maybe someone will test and provide the proper information. I think the main problem is they aren't ref. engineers...and they are pushing it to the ref. industry.

[casstrig]

One problem not covered in previous posts which im not sure if its been considered is Legonairs disease which became a known problem in the 80's after many people died.In evaporative condensers there is a treatment cartridge that fits into the pump body and gives a months coverage but im not sure if this is posible with this system or if locale sanitation laws would allow its use.

[GXMPLX]

One problem not covered in previous posts which im not sure if its been considered is Legonairs disease which became a known problem in the 80's after many people died.In evaporative condensers there is a treatment cartridge that fits into the pump body and gives a months coverage but im not sure if this is posible with this system or if locale sanitation laws would allow its use.

Legionella only appears if you have warm water exposed to ambient conditins.

In this case you use as cool water as possible and as clean as possible in a closed system being quikly evaporated (and 100% evaporated) so you wouldn't get legionella.

[GXMPLX]

pretty much....

How much is the slight energy savings worth. The company I refer to claims 30% savings but was not doing accurate testing. I'm all for saving money but their engineers only reply was it lowers compression ratio and that's it that's how you save 30%.

Do they mention 30% comparet to what? Old marketin' trick!

If it is total system energy I would belive it ... in the dessert!

I would have expected a long drawn out answer from an engineer. However he was only repeating himself constantly and refering back to his almost minimal testing.

I generally solved problems, never did tests they depend heavily on relative humidity.

If you have this data, and system performance catalog at different condensing temps you can estimate savings. Simply check the difference between DB and WB as ambient temperature.

Won't be much but have to multiply for hours at those working conditions, you can save energy.

I will admit they went full out engineering on explain how the mister "mists" Why not do the same with the energy savings after all that's why people would be buying it for.

Important. If it doesn't mist well I don't see the point of using it.

I can't see it being worth it...but maybe someone will test and provide the proper information. I think the main problem is they aren't ref. engineers...and they are pushing it to the ref. industry.

OK. Unfortunately we have hard water and misters block too often. Tough our climate would be ideal to use it, if you get a low cost water treatment I'll try it!

[ESCB]

Regardless of any comments relating to chemical corrosion or sanitary issues, you would be get ride of these comments just by using Humidifying Evaporative Pads instead, by which the rate of heat transfer on heat exchanger coils would be significantly highler due to higher heat capacity coefficient of humidified air.